The One Night Butterfly
by Lady StarFlower
Summary: Douma's lower lip juts out. "It's just the two of us here. Why don't you fall in love with me to pass the time?" Shinobu lands lightly on nothingness. "I can't give you something that has already been given away." Or; in which Giyuu and Shinobu learn something about fickleness. Smut. SPOILERS FOR CHAPTER 143 OF THE MANGA. Giyuu/Shinobu, with a slice of angst and sex.


_Aren't we all one-day butterflies,_

_not aware of time._

_Searching for partners or honey_

_until Death kisses us._

_Then in his arms, tenderly rocked,_

_waiting for a new chance_

_to fly away again_

_and join the dance_

_of the one-day butterfly_

O.O

In Limbo, everything is colorless, and she mourns because of it. It's cavernous, empty, and utterly silent.

Well, except for him.

"Shinobu-chan~" Upper Moon Two, Douma, is pouting next to her, trying in vain to catch her waist as she flits disinterestedly away from him. "Shinobu-chan, why don't you love me?"

"Don't try to touch me." Her voice, echoing in this huge empty space, is airy, sweet, and deadly cold. "You can go rot in the depths of hell."

Douma's lower lip juts out, childlike in his petulance. "It's just the two of us here. Why don't you fall in love and have some fun with me to pass the time?"

Her haori flutters like soft translucent wings as she lands lightly on the nothingness of Limbo. "I can't give you something that has already been given away."

The demon's mouth opens wide. "Whoa! There's another person you love already? How unfair!"

Shinobu looks away, but all she can see is darkness, darkness, and even more darkness. "Yes." Her whisper is thoughtful. "It's truly unfair."

O.O

"_Ah, you're staying up so late again!"_

_The Water Pillar grunts, but he doesn't budge from his position at the door. "Night is no time to sleep. We should be ready to kill any hungry demons in the area."_

_Shinobu hums, fluttering over to kneel beside him. "It's a bright night…and this house is protected by wisteria incense. We have this time to sleep, so why expend needless energy in brooding?"_

"_I'm not brooding." Giyuu says, crossly._

"_Yes, you are~" She singsongs, gently nudging his shoulder with her own. "I can tell because of the way your eyebrows are furrowed."_

_He stays stonily silent. Shinobu giggles lightly, like the tinkling of wind chimes, and adjusts herself snugly next to him. _

"_Very well." She sighs. "If you insist on keeping watch, I'll watch with you."_

_Giyuu shifts uncomfortably. "You don't have to do that."_

"_Oh, but I want to!" Shinobu smiles brightly. "It's not often I get a mission alone with the famous Water Pillar, after all."_

"_Don't call me that."_

"_Would you rather I call you Giyuu?" Shinobu grins, a merry expression coloring the lavender of her large eyes._

_He shudders when her name leaves her lips, intimacy ringing out in every syllable. It's too tender and far too gentle, and it makes his heart do a traitorous double flip. "Please be quiet."_

"_I can see why people don't like you." Shinobu smiles placidly, unflustered in his cold rebuttal. "But that's alright. Let's just look at the moon together, and I'll keep my thoughts to myself. Okay?"_

"_Mm."_

_And so in comfortable silence, they watch the moon sink into the horizon, clouds of silver and emerald green blanketing its clean white surface. _

O.O

"Caw! Caw! Dead!" The crow sweeping through the mansion screams. "Shinobu Kochou is dead! She died after a confrontation with Upper Moon Two! Caw!"

Giyuu stumbles.

"Giyuu-san!" Tanjiro cries out, but the older man just continues to run relentlessly, towards the direction of where Muzan is lurking.

Tanjiro feels tears well up in his eyes. Shinobu-san was such a beautiful and kind person…always smiling at him and giving Nezuko head pats. They didn't initially have the best first meeting, but she had grown on him, becoming the older sister he never had.

"Shinobu…"

Tanjiro starts. The stricken moan didn't sound like Giyuu at all. But it was unmistakably his senior's voice…and…

_This scent…it's so strong…._

The younger man almost staggers at how strong the smell of grief is. It's powerful, it's heady, and it screams of loss and anger, of anguish and overwhelming regret.

He's smelled sadness. He's smelled anger. But this…it's heartbreak; stricken, shattered, heartbreak.

And yet Giyuu keeps running, unfaltering in his relentless beeline straight towards Muzan. He runs and runs, and Tanjiro is shocked at how calm he appears on the outside. He's pale, but his lips are set in a straight line and his hand is tight on his sword.

"Giyuu-san…?" Tanjiro finally ventures.

"…We must focus on the task at hand." His voice is stern, unerring, and hollow. "We must not let her death be in vain."

Tanjiro fiercely scrubs at the tears that had gathered on his eyelashes. "Y-Yes!" His steps quicken to match Giyuu's in pace.

Until their next battle, he never hears Giyuu speak again.

O.O

"_Hm? What are you doing here, so far from the rest of the celebrations?"_

_Giyuu starts at the proximity of her velvet-warm voice, and he looks down to see her frowning at the sake bottle clutched in his hand. _

"_Wow, you're actually drinking tonight!" Shinobu giggles, her laugh sounding honeyed and dizzy as she stumbles a bit on the gravel of the Ubuyashiki gardens. _

_His hand catches at her waist before she falls. "You seem pretty drunk yourself, Shinobu."_

"_Mmm, what if I am?" She laughs, her eyes filled with dreaminess as she gazes at him with clear intent. Her body melts against his like snow in the sun. "It's the New Year's Celebration, and we deserve a holiday after that fight with the Bell Demon." _

_Her voice goes low, like deep amber honey. "Don't you think so, Giyuu?"_

"_Shinobu." His voice is low, a warning. But it's a feeble warning, a hypocritical warning, for his arms are already snaking around her waist, slow and sinuous like the water he channels. _

"_I like it when you call me that." She sighs, her hips moving forward to press gently against his body. He nearly jumps out of his skin when she grinds up against him, fluidly, teasingly. _

"_Shinobu…."It's a strangled groan that leaves his lips. It's a sound he's almost ashamed of._

_She stops. "Do you not want this?" Her large eyes, though hazy with intoxication, look intently at him. "We can stop-" _

_He grabs her, he seizes her small waist in his hands, and pulls her close. She flies forward and her hands come to brace herself on his chest. He's not wearing his uniform tonight, just a thin yukata to keep out the cold. _

_Giyuu can feel the heat from his palms on his chest, and the way it makes him shiver. _

_Shinobu smiles, a wicked smile that leaves him breathless. "I'll take that as a no."_

_She kisses him. _

_It's a deep kiss, a fierce kiss, an urgent kiss. It's a rather sloppy one as well. Their teeth clack together and he doesn't know where to put his hands. But she rises on her tiptoes, and cups his jaw with her hands. She kisses him and kisses him, over and over, and he kisses her back with a desperation that surprises even himself. _

_It's something deeper than alcohol fueling them now. _

_Without breaking contact, he spins them around and pushes her body until her back hits the wall of the gardens. Her legs automatically lock around his waist and she moans at the way he worships her mouth. He sighs when her hands slip up to tangle in his hair. _

_Her hips buck into his and for a moment he sees stars. _

_His hands grab at her yukata, pulling at the sash until it falls open. She has to stifle her whine into her hand as he lavers a strip on her breast, biting at her collar where it could be hidden by her uniform. He bites her, he licks her, as she writhes beneath him gasping in ecstasy. _

"_Giyuu…Giyuuu…" Shinobu gasps, again and again. He muffles a groan when she grinds fiercely down on his erection, and she all but snorts at his reaction. _

"_You are a funny person." She teases, even when he glares at her halfheartedly. She reaches down to untie his sash, and suddenly he's in awe at this small woman, at this butterfly warrior who treads lightly on upturned soil and slits demon throats with nothing more than a charming giggle. _

_He's not in awe. He's…he's…_

_Giyuu gasps loudly as she takes his cock into her small, warm hand. She's smiling again, that devilish smile that surely bides no good for him. _

"_Now do be quiet." She instructs him, lifting her skirts. "It would be embarrassing if the others heard us."_

_She sinks slowly onto him. _

_They both moan in unison as he fills her. Hers is strangled, high pitched, and his is muffled in her shoulder. For a moment they are frozen, bathed in moonlit shadow as they both try to reign in their breathing. He's the first to recover, and he kisses her ear lightly. "Are you…"_

"_Yeah, yeah." Shinobu sounds breathless and some perverse part of him is deliriously delighted about that. "I'm okay."_

"_Good." He replies, and then begins to move._

_It's ecstasy. It's a tidal wave, a monsoon of glory, and Shinobu's increasingly broken voice does nothing but fuel that pleasure. She's clutching onto him so tightly she's going to leave marks, but at the moment he couldn't care less, showering her face with open-mouthed, frantic kisses as her hips buck up to meet his own punishing thrusts. _

_Soon, she gasps out his name, and he's never heard anyone say his name so earnestly, so brokenly, so wantonly, that it tips him over the edge, smothering his debauched cry into her neck. She follows soon afterwards, her wail ringing clear into the air._

_They spend a moment interlocked for a while, trying to slow their heartrates. He pulls out of her, and they both hiss at the drag of oversensitive flesh._

"_Would you look at that." Shinobu smiles at him, a little shyly. "Now I'll have to go ask the herbalist for some rather embarrassing herbs tomorrow."_

_Unbidden, an image of a laughing child with Shinobu's dancing eyes makes his heart do an unexpected flip. The knowing look on her face makes him realize that she's thinking of it as well._

"_I'm sorry." He blurts out._

_She raises an elegantly curved eyebrow at him. "What for? It's a perfectly reasonable response." She carefully reties his yukata sash, tying the knot with clinical precision. "Maybe…" Shinobu falters. "Maybe afterwards, when we've served our time as Demon Slayers."_

_She smiles at him. "Afterwards, yeah?"_

_A bright future…a promising future…_

_Giyuu nods slowly, savoring the thought, a foolishly happy one. "Afterwards..."_

O.O

"Waaah, Shinobu-chan, that's such a sad story!" Douma is weeping loudly and unashamedly into his hands. "Your life had to end so tragically and so short! Your daughters could've been very beautiful women! Oh, how lovely they could've tasted…"

"You are vile." She says in disgust, stepping away from him. "I don't even know why I told you that."

Douma brushes the last of his tears aside. "Aww, Shinobu-chan, don't you realize?" His grin is easy and light, but there's a vindictive sharpness behind his charm. "You're dead now. Your life has flashed before your eyes, and so you needed to share your feelings, because Giyuu would never hear it from your lips again."

Shinobu returns his cold grin with one just as poisonous. "You're not just a bastard, but you're a stupid one." She dances away from him. "Giyuu and I have buried that hatchet long ago."

"It won't do you any good lying to yourself, you know!" The demon calls after her. "I can smell the regret off you! You will suffer eternally unless you learn to realize that!"

Shinobu shuts her eyes and lets go.

With a liquid sigh, Limbo releases her, and with the silent flutter of black wings, Death comes to claim her.

O.O

"_I never thought that you would come visit me here."_

"_Silly. This is a dream, don't you know? I can come visit you any time you want."_

_His eyes are so sad. "Shinobu…What about afterwards?"_

_Her smile is grieved. "I'm sorry. I miscalculated. I forgot about the horrors of our reality." She glides away from him. "You will have to make your own afterwards."_

_His quiet voice shakes. "I'll miss you."_

"_I'll miss you too." She turns to smile at him, that ever present sparkle in her eyes dimming. "I'll wait for you, Giyuu Tomioka. Please don't come to me fresh and young. I want you to live a long, old life. It would be dull if you had to follow me so quickly."_

_His hand reaches for her. She's fading."Shinobu…" _

"_Goodbye, Giyuu." Her voice winks out, and there is nothing when he wakes up. Only a single lavender butterfly flitting away from his forehead as he buries his head in his hands and finally, finally, gives voice to his grief. _

fin

**AN: **Title is inspired by the One Day Butterfly, which I have included in my work. I do not take credit for the authorship of that particular poem, I just thought it was fitting.

Thank you for reading! Practice safe sex, ya'll!


End file.
